MeiG_SLM156_Hardware Design Manual
MeiG Smart Technology Co., Ltd
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3.6.2 Decrease Voltage Drop
The power supply range of SLM156 is from 3.3V to 4.2V. In order to reduce voltage drop, it is
suggested set a low ESR 100uF filter capacitor and three ceramic capacitors (100nF, 33pF and 10pF)
near VBAT pin. When external power connects the module, The width of lines should not be less than
2mm.
In addition, in order to guarantee the stability of power, it is recommended to add zener diode with 5.1V
and power over 0.5W onto the power. The reference circuit for power supply is as follows:
Figure 2 Reference Circuit for Power Supply
3.6.3 VDD_EXT Voltage Output
If SLM156 module turns on normally, there is a voltage output of 1.8V, current load 80mA in PIN64. You
can use the output voltage as external power supply, for example level reference, and judge if the
module is turned on by reading pin level status.